If you can find premium torso then get lightning platinum vest,molten platinum vest or the monke torsos(fractured heat armor, rusty energy armor, hollow spectral armor) try not to use hardened platinum vest cuz it's not that good for legendary to mythical.
If you are looking for non premium torsos, I recommend you get windigo and make it max mythical or stop midway if you have either of the two platinum vest I mentioned above. Also, try to get rid of battery armors as they are really bad once u go rank 10+(actually 12 in most cases) you will need alot of regeneration modules if you gonna continue using so I suggest you replace battery with windigo.
Oh btw, premium torsos are torsos that have rarity starting from legendary and they go till divine. They are harder to get but worthit. You should also upgrade your nightfall and your leg in the meanwhile (try finding premium torso or windigo alongside +modules)
Here is the tier list of torsos made by @Electro, my tierlist is nearly same to his so I am gonna send you his one for reference.
Yes, use windigo till you get molten platinum vest, if you look at the stats in https://workshop-unlimited.vercel.app/, you will see molten platinum vest(heat variation) is just the upgraded version of windigo with not much difference just higher physical resistance(which is very important in top ranks) and lightning platinum vest(energy variation) is just upgraded naga with higher physical resistance. Also, windigo and naga have better heat and energy stats by default so keep that in mind, you might need to upgrade your modules a bit if you gonna use mpv or lpv.
Atomic441's post in Rate my build and give me suggestions was marked as the answer